United Nations chief Ban Ki-moon is in Burundi, where tension is rising ahead of a June 28 presidential poll.

His visit Wednesday comes days after the main opposition and five other parties pulled out of the election, saying they believe the vote will be rigged.

Speaking from the capital, Bujumbura, Wednesday, Mr. Ban said he would meet with President Pierre Nkurunziza, as well as electoral commission officials, political party leaders, members of parliament, and representatives of civil society groups.

He also congratulated Burundians for reaching peace following a 12-year civil war.

The opposition parties accuse election officials of failing to prevent fraud during local polls last month. European observers said the elections met international standards.

Official results showed the ruling National Council for the Defense of Democracy winning 64 percent of the vote.

Despite the opposition's boycott, the electoral commission says the presidential poll will continue as planned, with President Nkurunziza running unopposed.

Meanwhile, Burundian officials said Wednesday they have banned further demonstrations by political parties protesting the increasingly fragile electoral climate.

This year's elections are aimed at capping a transition to democracy started by peace agreements that ended the civil war in 2005.